Diff Breathers - Really Required?

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Date: Thu, 15 May 1997 15:18:49 -0700
From: Randy Ring 
Subject: Diff Breathers (real or gadgetry?)
To: "'Toy4x4@tlca.org'" 

I have read, seemingly, more text on "diff breathers" than just about 
any subject in the last several months. You guys have me paranoid about 
my diffs now!  I have had my 86 and my 85 Toys in water countless times.
I even "floated" once for about 10 feet.  I have never had any water
leak into the diffs (or anything else for that matter).  I'm running the
stock Toyota "little diff caps".  Have I been lucky or is there a REAL
problem with water leaking into the diffs.  Will you all with experience
in this area please tell me?
Thanks,
Randy "Gnarls" Ring
85 Toy Std. cab, 22R
Randy_Ring@environ.com

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Date: Thu, 15 May 1997 21:46:00 -0400 (EDT)
From: Spinnetti@aol.com
Subject: Diff Breathers (real or gadgetry?)
To: Toy4x4@tlca.org

you've been lucky. your stock diff caps are probably rusted shut. This only
becomes a problem if you work the truck hard. The rear end heats up and
begins to blow fluid past the axle and pinion seals. Change your fluid
promptly after a dunking!

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Date: Thu, 15 May 1997 23:47:18 -0400 (EDT)
From: DRM033@aol.com
Subject: Diff Breathers (real or gadgetry?)
To: Toy4x4@tlca.org


I go through lots of water, and my little stock caps have done just fine.
 The extended breathers are not a "must", but they sure make for cheap
insurance!

David
DRM033@aol.com

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Date: Thu, 15 May 1997 23:56:36 -0800
From: "CONRAD" 
Subject: Diff Breathers (real or gadgetry?)
To: 


You are the reason everyone else gets stuck with bad luck, you have all the
good luck!!  YES, you have been very lucky.  Do not keep tempting fate,
extend the breathers!
jc

Jack Conrad,  BIG TOY, TLCA # 3851
conrad@mosquitonet.com, North Pole, AK
84 FJ-60, coils over  leaf-over, 350,38s, ARB
92 Extra-Cab, coils over leafs, 5.29s, ARB, 35s
Land Cruiser, don't leave the pavement without one!!

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Date: Wed, 9 Sep 1998 10:41:19 -0500 
From: "Tong, Donald L" 
Subject: RE: Diff Breathers

> Jon Brandt wrote: "Forget about the fancy valves and adaptors. I just
> shoved the original valve into the end of the fuel line."
> 
I know I exchanged messages about this before with someone before (possibly
Jon), but for the benefit of anyone new trying this, it's my opinion that
using the original valve pretty much defeats the purpose of running the
extended breather line.  The original valve is designed to vent as pressure
builds up in the diff (from heat buildup).  But when the diff cools (like
when it goes through water) negative pressure occurs.  Since the valve seals
shut, the pressure has to be relieved by other means.  It has been suggested
that this other means is that water leaks past the seals into the diff.  I
don't think anyone as suggested that water comes in through the valve,
although it's certainly a possibility if the valve gets dirty.

By running an extended breather line with no valve on top (i.e., just a fuel
filter to keep dust out) you allow the diff to breath in both directions.
If you use the original valve, the valve still closes shut and you're back
to letting water back in through the seals.  Or, if water was getting in
through the valve, it's now breathing correctly but could let in dust.

Jon says he's seen no problems using the original valve and I can't really
argue with him on that.  But I do know that before I put in my extended
breathers I never got water in the diff either.  So certainly where and when
you go plays a part.  Another explanation might be that the extra air in the
breather hose (or the hose collapsing under negative pressure) is enough to
keep the diff from pulling water through the seals.  Either way, I figure
why re-use the original valve and take a chance when you can get cheapy fuel
filters for a buck and know the diff is breathing in both directions.

Anyway, I don't really mean to suggest that Jon is full of bunk.  If he says
it works for him than I can't say otherwise.  But I think that anyone
installing the extended breather line should understand the theory behind
making this modification.

Don Tong
'91 4-Runner

============================================================================
Toyota 4x4 page: http://www.off-road.com/4x4web/toyota

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Date: Wed, 09 Sep 1998 16:17:59 -0400
From: Charles Brooks 
Subject: Re: Diff Breathers


When I did the extension I thought the same thing so out of curiosity I put
the stock valve on the end of a 1 foot piece of tubing andtried to suck air
thru the valve. I could get quite a bit of air thru the valve. Then I 
immersed the valve in a bowl of water and tried the same thing. I wasn't
able to get ANY water thru the valve. That leads me to believe that the
valve only closes if it's under water, so I went ahead and put it on the
extension with the idea in mind that by the time the water got to the
extended valve there would be little to no vaccum left.

Just my .02    :)

Charles Brooks

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Date: Sat, 19 Dec 1998 13:16:12 -0600
From: "Chuck & Birgit" <4RUNNER4X4@prodigy.net>
Subject: Axel Vent

Jay, the Part Number is 90404-51026   Discription: Union
They list for $3.03 and Jeff Watson Jay Marks Toyota can get them for $2.27
that was back in Feb. at 1-800-327-2087

I've used this for my 85 4Runner       Chuck

Date: Fri, 18 Dec 1998 13:03:24 -0700
From: "Jay Kopycinski" 
Subject: Axle vent........Toyota EFI fitting part number ???
Can someone please email me the Toyota part number
for the barbed EFI fitting used to setup axle vent lines?
(I have the Nissan number, but would like a Toy one.)
Thanks.
Jay Kopycinski    '85 Toylet  (ROKTOY)

Chuck & Birgit's 4Runner Webpage
http://members.tripod.com/~schladenhauffen/index.html


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